Optical instrument



H. F. KURTZ EI'AL OPTICAL INSTRUMENT Filed OGLA 13, 1943 oct. 15,1946.

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Patented Oct. 15, 1946 UNITED STATES PATENT OFFICE OPTCAL INSTRUMENT v Henry F. Kurti, Rochester;` adltbert G. More risen, Greece, N. Y., as'signosl to' Bausch & Lomb Optical Company, Rochester, Y.,l Aa corporation of New York Application 'october 13, 194e", serial No. 506,676

8 Claims.

This invention relates to optical instruments, such' as telescopes; and more particularly to bi nocular telescopes; This application is a con*- tinuatin-i'n-part of our co-pendingmapplication Serial No. 456,238 filed August 26, 1942. s

Inf binoculars heretofore proposed, the eyepiece or ocular tube has been carried by a mounting" tube usually threaded into the endwall or a detachable cap forming an end Wall of the body of the instrument. `In the instrument of" the present invention, the mountingtube is made in; tegral with a detachable cap forming the end Wall f thesame and the threaded joint on the exterior surface of the` instrument is thus climi;

Hated n The ocular tube istelescopica-lly mounted w'itlie inthe mounting tube and the axis of the ocular tube is hel'd coincident with the axis of the mounting tube through guide surfaces formed the exterior" of the' ocfu'lartube and the interior of the mounting tube. The guide surfaces not' onlyV hold the axis of the` ocularv tube coincident with the axis of the mounting tube during the axial movement of the ocular but also tend to sealth'e telescopic connection between the two niloesl.` Y

As* the VAmounting tube actually carries' and is' used to'positiontlie optical elements of the ocular relativeto the body, means areprovided for 1ocatingtnecapielative toa uniplanar surface establishing 'aireference plane used to locate and mount the' optical elements of the instrument.

s To this end, the cap isff'ormed with a uniplanar' surface held AnormalA to the axis of the mounting tube and adapted to engage the surface of the body defining the reference plane'. In the elnbodiment of the invention now preferred, this" surface is formed on a shoulder of thebody ad'- jacen't the end closed by the cap and the en-V gaging'surface of the cap is formed on the end face of a flange adapted to clrcumscribe theopen end of the body. As the axis ofthe mounting tube is normal to the plane of the endface of the iiange,- the axis of the tubular member and consequently the axis of the ocular will be'no'r'f mal to the reference plane when the cap is mounted to the body. 1

To locate the axis of the ocular in apredeterminedI desired position, a locating surfaceis formed on the walllof the body' of the' instrument and is engaged by a cooperating surface formed onlthemounting tube-when thecapfis-secured to n thebl'ady.` The locating surfaceisso formedirelativer` to thelreference plane thatv the axis of` mounting'i tuber-Will -be located and heidi -ilnf a pre-4 is reduced to a simple assembly operation easily completed by the ordinary Worker.

To seal the jointure between the cap and body,` agasi-et is placed on the end face of the body and ce'mpiesse'd when the surface on the ange of thecap" is brengt-'iii into close engagement with the uniplanar suria'ceoi thev body;- In previously proposed binoculars, Where tl'ie end surface of the body' has been used as'v the reference plane, cate had te betalen 'that the gasket was of constant thicknessl and that `it Was evenly cornpressed over its entirety, 'fr otherwise the cap would not'be disposed in the desired angular pcsition relative to` the optical` axis cf the objecti-V.

At the objective; the line of jointure between all suriaees ithe" objective mounting are sealed by means oialga'sk'et held in place by a locking ring which locks the" objective in position. This ring, in the now preferred form of thepresent invention,A isheld against movement byv a guard cap secui'ed tothebbdy ofthe instrument, which further seals the body againstv entrance of moisture.

Other features and advantages' Aof the' present invention willbe apparent Vfromthe-sfollowing description' takenlinconjunction with the accom*- panying drawing, in which: Y

Fig. 1` is an elevational yievv of one body unit of the binocular illustrative ofthe present invenf Fig.` 2i sg'.' SeGOhalVeW' partly ltr elevation 0f the upper endlof thebi'ncc'ular. 4

8 istia section taken alc'nglline: 3-1-3 of Fig. 4v is a View similari to nig. zbut snowingA the: 4objc-active endf ci the? binocular-.-

As both" E'Ody units' Gif the instrument CifI the in thence preferred form of the presenplirivention, the body is preferably molded Withthe opposite ends' open to permit the prism elements to b'elr'no'e easily assembled therewith. The one integrally formed therewith a mounting tube I2 normally projecting outwardly on opposite sides thereof. The interior surface of the outer portion of the tube I2 is threaded and takes a threaded ocular tube I3 carrying eyepiece lens elements, one of which is indicated at I4 and shown locked in position within the same by a threaded band I5. The eyepiece elements are accurately mounted within the tube I3 with the optical axes thereof coincident with the axis of the tube.

To align the axis of the ocular tube I3 with that of the mounting tube I2, an accurately formed cylindrical surface II is machined-on the interior of the tube I2 and this surface, together with a cylindrical surface I8 concentric therewith and formed on the interior of a ring I8' 4 termined distance from the reference plane established by the-face I9.

To locate the axis of the ocular in a predetermined desired position, a locating surface is formed on the mounting tube I2 which, when brought into engagement with a correlated surface on the body, xes thev axis of the mounting tube in the desired position. As the ocular tube will have already been positioned in the mounting tube, the assembly of the body and cap brings the optical axis of the ocular tube into the desired relationship with the reference plane determined by the surface I9. Although the loeatingA surfaces may be formed in any manner threaded into the opposite end 'of the tube I2,

engages spaced portions of the exterior surface of the ocular tube I3 and holds the same in the desired position relative to the mounting tube I2. The annular passage between the two tubes is very effectively sealed due to the threaded connection and the close engagement between the exterior surface of the tube I3 and the spaced bearing surfaces I 'I and I3.

In the assembly operation, the ocular tube is merely threaded into the mounting tube and as the two surfaces I'I and I8 will align and hold in alignment the assembled tubes, the step of aligning the ocular tube with the mounting tube is reduced to a simple assembly operation easily completed by the ordinary workman.

Furthermore, in prior devices, where the mounting tube was threaded into the body, small chips, out by the meshing threads as the tube and body were assembled, dropped into the body and if not remo-ved tended to foul the surfaces of the optical elements of the body.

After the ocular tube I3 has been assembled with the mounting tube I2, the cap can then be secured to the body I of the instrument. As the mounting tube I3 actually carries and is used to align the eyepiece of the instrument relative to the same, it is important that the cap be so mounted to the body that the axis of the mounting tube will be located in a predetermined position relative to the optical axis of the other elements carried by the body, for unless this is so, the optical axis of the eyepiece will not be in proper alignment with the optical axis of the other elements.

To insure that the axis of the mounting tube I2 will be in the desired position after the cap is assembled to the body, the body is formed with a shoulder adjacent the end enclosed by lhe cap and the face I9 of the shoulder is accurately machined uniplanar. In the preferred form of the present invention, the face I9 is used to establish a reference plane for mounting and locating the optical elements of the instrument. The cap is formed with a depending flange and the end face 2i! of the flange is machined uniplanar, and is adapted to engage the surface I9 when the cap is mounted on the body. The plane of the face 2l) is maintained normal to the axis of the mounting tube I2 so that when the cap is mounted to the body with the surfaces I9 and 2U in facewise engagement, the axis of the tubular member, and consequently the axis of the ocular, will be normal to the reference plane established by the surface I9.

Furthermore, itwill be obvious that the flange, if held to a predetermined length, will space the elements o-f the ocular tube the proper prededesired, it is now preferred to form the same cylindrical and, in the illustrated embodiment of the invention, the one surface 2| is formed on the adjacent faces of the blocks 22 cast integral with the wall of the body Il) and the inner portion of the wall of the body intermediate the blocks. The axis of the surface 2| is normal to the plane of the surface 2U and forms a relatively large locating surface cooperating with a similar machined surface 23, formed on the exterior of the lower portion of the tube I2. Thus, when the cap is placed in position on the body I0 with the two surfaces 2I and 23 in engagement, the axis of the ,tube I3, and consequently the optical axis of the eyepiece, will not only be held normal to the reference plane but will be also located in the desired position relative to the same.

To seal the body at the end closed by the cap I I, a gasket 2li is seated on the end face 25 of the body Ill and is clamped against the same by the cap I I as the latter is drawn up against the body by screws 25 received in tapped holes formed in the blocks 22 and a boss 2l integrally formed with the body during its forming operation. The gasket has a greater thickness than the distance between the end face of the body member and the inner surface of the ycap after the uniplanar surfaces of the body and cap are in facewise engagement so that the the gasket is compressed after the cap is mounted to the body. In previously proposed binoculars where the end face of the body has been used as the reference method, care had to be taken that the gasket was of constant thickness and that it was evenly com-,-

pressed over its entirety, for otherwise the cap would not be disposed in the desired'angular position relative to the optical axis. It will be obvious that this dilculty has been obviated by the construction of the present invention.

The tube I3 carries an eyecup 30 andra diopter band 3| which telescopes the upper portion of the tube I2. The tube I2 is marked with an index line 32 cooperating with the usual graduations. 33 of the diopter band. The diopter band rotates with the tube I3 during the adjustment thereof longitudinally-ofthe tube I2 and will indicate to the user the particular settingV of the eyepiece in diopters. I

In the now preferred embodiment of the device of the present invention,V the ring I8 forms a stop collar for limiting movement of the ocular tube I 3 and will prevent the same from being threaded out of the tube I2. The ring in one limit of adjustment limits the movement of the tube I3 by engaging the exterior threads thereof, and in the other limit, the underneath surface of the flange 34 of the diopter band 3 I.

The objective 35 of the binocular of the presenty invention is carried by a cell 36 and held in place on the cell 36 by a bezel ring 31. The cell 36 engages an annular seat 38 formed' Within the formed on said body adjacent said open end, said shoulder comprising a uniplanar surface forming a reference plane; a flanged cap for closing said open end; a tubular member formed integral with said cap; a uniplanar surface on the flange of said cap adapted to engage the uniplanar surface of said body when said cap is mounted thereon for holding the axis of said tubular member normal to said reference plane; a locating surface carried byv said tubular member; and a locating surface formed on said body and adapted to engage the locating surface of said tubular member for holding the axis of said tubular member in a predetermined position relative to a predetermined axis normal to said plane.

7. In an instrument of the type described, a body having an open end; an exterior shoulder formed on said body adjacent said open end, said shoulder comprising a uniplanar surface forming a reference plane; a cap for closing said openrend; a depending flange carried by said cap; a tubular member formed integral with said cap; a uniplanar surface on the iiange of said cap adapted to engage the uniplanar surface of said body when said cap is mounted thereon for holding the axis of said tubular member normal to said reference plane; a locating surface carried by said tubular member; a locating surface formed on said body and adapted to engage the locating surface of said tubular member for holding the axis of said tubular member in a predetermined position relative to a predetermined axis norma1 to said plane; and a gasket of compressible material carried by the end face of said body, said gasket being compressed when saidcap is secured to said body with the uniplanar surfaces in facewise engagement.

8. In an instrument of the type described, a body having an open end; a shoulder formed on said body adjacent said open end, said shoulder comprising a uniplanar surface forming a reference plane: a cap for closing said open end; a tubular member formed integral with said cap; a flange on said cap adapted to circumscribe said body adjacent the open end thereof; a umplanar surface on said flange adapted to engage the uniplanar surface of said body when the cap is secured thereto for holding the axis of said tubular member in a'prdetermined angular position relative to said reference plane; and a gasket of compressible material carried by the end wall of said body, said gasket having a thickness greater than the distance between said end Wall of the body and the interior surface of the cap so that said gasket is compressed when the cap is secured to said body and the uniplanar surfaces are in facewise engagement.

HENRY F. KURTZ. ROBERT G. MORRISON. 

